| | Stillwater, MN | Centennial, CO | United States |
| Population | 19,243 | 107,972 | 329,725,481 |
| Female Population | 50.3% | 49.6% | 50.5% |
| Male Population | 49.7% | 50.4% | 49.5% |
| Median Age | 41.9 | 41.4 | 38.4 |
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| Population - 2010 | 18,671 | 100,294 | 309,327,143 |
| Population - 2000 | 15,143 | 100,309 | 285,036,114 |
| Population - 1990 | 13,882 | 81,946 | 251,960,433 |
| Pop. 2000 to Now | 30.1% | 9.8% | 15.6% |
| Pop. 1990 to Now | 41.9% | 34.4% | 30.8% |
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| Population Density | 2,390.7 | 3,650.5 | 93.4 |
| Land Area | 8.0 | 29.6 | 3,531,905.4 |
| Water Area | 1.0 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Stillwater, MN | Centennial, CO | United States |
| Age 0 to 4 | 4.4% | 5.4% | 5.9% |
| Age 5 to 9 | 5.7% | 6.5% | 6.1% |
| Age 10 to 14 | 8.3% | 7.4% | 6.6% |
| Age 15 to 17 | 4.0% | 4.1% | 3.9% |
| Age 18 to 20 | 2.5% | 2.8% | 4.0% |
| Age 21 to 24 | 5.1% | 3.5% | 5.2% |
| Age 25 to 34 | 12.1% | 11.3% | 13.8% |
| Age 35 to 44 | 12.7% | 14.8% | 12.9% |
| Age 45 to 54 | 12.9% | 13.6% | 12.6% |
| Age 55 to 59 | 7.6% | 7.0% | 6.7% |
| Age 60 to 64 | 5.5% | 7.2% | 6.3% |
| Age 65 to 74 | 11.8% | 10.2% | 9.6% |
| Age 75 to 84 | 6.4% | 4.3% | 4.5% |
| Age 85 and over | 1.1% | 1.9% | 1.9% |
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| Race | | | |
| | Stillwater, MN | Centennial, CO | United States |
| White | 86.0% | 78.0% | 59.4% |
| Black | 2.3% | 2.6% | 12.2% |
| Asian | 1.1% | 5.9% | 5.6% |
| Native American | 0.2% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.5% | 0.5% | 0.4% |
| Two or More Races | 3.4% | 3.6% | 3.2% |
| Hispanic | 6.5% | 9.0% | 18.4% |
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| Marriage & Family | | | |
| | Stillwater, MN | Centennial, CO | United States |
| Married Population | 54.7% | 60.2% | 49.8% |
| Currently Married | 54.3% | 59.4% | 48.0% |
| Married but Separated | 0.4% | 0.7% | 1.8% |
| Single Population | 45.3% | 39.8% | 50.2% |
| Never Married | 29.8% | 25.1% | 33.8% |
| Divorced | 10.4% | 10.9% | 10.8% |
| Widowed | 5.1% | 3.8% | 5.6% |
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| Household Size | 2.50 | 2.63 | 2.60 |
| Households | 7,517 | 40,344 | 124,010,992 |
| Family Households | 5,211 | 29,979 | 80,755,759 |
| Married couple, w/children | 30.9% | 36.2% | 30.5% |
| Married couple, no children | 48.2% | 46.3% | 42.9% |
| Non Family Households | 2,306 | 10,365 | 43,255,233 |
| Single householder, w/children | 13.6% | 10.7% | 15.8% |
| Single householder, no children | 7.2% | 6.8% | 10.8% |